Lens



June 11, 1935. I R. KovAc LENS Filed Sept. 14, 1934 Patented June 11, 1935 UNITED sTATEs.v

LENS

Raolph Kovac,'Chicag-o, Ill., assignor to American Automatic Devices Co.,` Chicago, Ill.. a corporation of Illinois Application September 14, 1934, Serial No. 743,964

3 Claims.

My invention relates to lenses and particularly to combination projector and reflector lenses, and it has for its object the provision of a new and improved form and arrangement of cooperating 5 parts whereby the lamp in which the lens is used shall be effective for projecting a distinct pen-- cil of light from the source of light in the lamp along the axis of the lens while at the Vsamev time being so illuminated as to have high visibility from points far removed angularly from the axis of the lens and particularly from points directly' or substantially at right angles to the axis of the lens. It is another object of my invention to provide a construction of the type named such that the lens shall be very efiective as a reflector for sending rays backwardly to points near the source of light when illuminated -from' points outside of the 1amp,,as from the headlights of an approaching car, effective in this manner with respect to light from various angles relatlvely to the axis of the lens and particularly with respect to light from a source either substantially in the line of the axis or substantially at right angles to the axis of the lens. i It is one of the objects of my invention to provide an arrangement by virtue of which effective projection of light may be effected through the lens and effective .refiection shall be attained from the lens without the necessity for having F the lens manufactured upon a precision basis, whereby a product manufactured upon a commercial scale with comparatively high tolerances as to size and shape shall be acceptable for the purposes for which it is designed.

It is another object of my invention to improve devices of this type in sundry details hereinafter pointed out. The preferred means by which I have accomplished lmy several objects are illustrated 'in the drawing and are hereinafter specifically described. That which I believe to be new and desire to cover by Letters Patent is set forth in the claims.

In the drawing- Fig. 1 is a central Vertical section through a prefered form of lamp comprising my improved lens;

Fig. 2 is a back face view of my lens; and

Fig. 3 is a cross sectional view taken substantially at line 3-3 of Fig. 1.

Referring now to the several figures of the drawing, in which corresponding parts are indicated by the same reference characters, IO indicates a casing) of sheet metal in the form of a cup having a sleeve ll mounted radially in position in the side wall, with a spacing sleeve |2 secured on the outer end of the sleeve for spacing the casing IO from a bracket I 3 to which the casing is secured by means of a nut I 4 mounted on the lower end of a threaded sleeve 5 formed with or rigidly connected to the sleeve 5 ll. An electric light bulb |6 is secured in any approved manner in the upper end of the sleeve H and having electrical connection with a lead |1 for energization of the filament of the bulb. from any suitable source of electrical energy.

Upon its side wall portions opposite the bolt 16, the casing I ll is provided with brackets |8 serving as the support for a lens 19 which is removably secured in position in the front end of the casing l' by means of a split ring 20 co- '15 Operating with an inwardly turned flange 2| at the forward edge of the casing.

' As is best shown in Fig. 1, the lens |9 is formed concavo-conve'x, with its outer or convex face having a continuous curvature, the lens in 'its preferred form comprising sllghtly' less than a half of a prolate spheroid. The inner or concave face of my improved lens is arranged in vconcentric steps at its middle portion comprising substantially plane annular zones 22 alter- 25 nating with substantially frusto-conical annular zones 23, with a plane .circular zone 24 at its middle point. At its outer edge portion outside of the stepped formation, the inner face of the lens comprises. a series of diverging ribs 25, each of which is defined by faces standing at substantially'right angles to each other. In the arrangement shown the portion arranged in concentric steps comprises substantiallythe middle two- 'thirds of the lens diametrically thereof. In the arrangement shown the ribs 25 are positioned at an angle of approximately 30 from thevaxis of the lens. t

` I have found in practice in the use of my device that when the bulb [6 is illuminated by a current through the filament a distinct pencll of ,light is projected forwardly through the lens with such penoil spreading sufliciently that theray is clearly visible not only from directly in front of the lens but also from points located at some-litle'distance transversely from the axis of the lens. With the bulb I 6 illuminated, the lens 19 is clearly visible directly from the side at points located at considerable distances from the 50 lamp at right angles to the axis of the lens. I have found also in practice thatl when the bulb IG is burnt out a ray of light from an external source falling upon the lens is reflected backg wardly to its source and with sufllcient spread for enabling vone in the neighborhood of the source of light to detect easily the presence of the lens and to determine readily its color. This refiection backwardly to the source of a light located externally is particularly effective when such external light strikes the lens either direotly from the front or directly from one side.

I have found in practice in the use of my improved lens that there is an effective cooperation between the stepped portions of the lens and the ribbed portions of the lens for both the projection and the refiection of light whereby the device is very effective for the purpose for which it is designed.

While' I prefer to employ the form of device as shown in my drawing and as above described. it is to be understood that my invention is not limited to the form shown except so far as the claims may be so limited by the prior art.

I claim:--

1. A concavo-convex lens having its convex side smooth, and having its concave side at its middle portion arranged in concentric steps and provided at its outer portion with diverging ribs each positioned at an angle of not more than approxiznately 30 from the axis of the lens.

2. A concavo--convex lens having its oonvex side smooth, and having its concave side at its middle portionv arranged in concentric steps and provided at its outer portion with diverging ribs each positioned at an angle of not more than approximately 30 from the axis of the lens, each of said ribs being defined by faces standing at an angle of approximately 90 with respect to each other.

3. A concavo-convex lens having its convex side smooth, and having its concave side at its middle portion arranged in concentric Steps transversely positioned with respect to the axis of the lens and comprising substantially plane zones alternating with substantially frusto-conical zones, the outer portion of said concave side being provided with diverging ribs each positioned at an angle of not more than approximately 30 from the axis of the lens, each of said ribs being defined by faces standing at an angle of approximately 90 with respect to each other.

RUDOLPH KOVAC. 

